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Integration of Zero-Valent Metals and Chemical Oxidation for the Destruction of 2,4,6-Trinitrotoluene within Aqueous MatricesHernandez, Rafael 13 December 2002 (has links)
The Department of Defense (DoD) has numerous sites that contain groundwater contaminated with 2,4,6-trinitrotoluene (TNT). The currently applied technologies for treating TNT contaminated waters are carbon adsorption and chemical oxidation. Carbon adsorption is a non-destructive technology, which could create future liability issues and is inefficient at relatively low TNT concentrations. On the other hand, application of chemical oxidation for the treatment of TNT contaminated water generates trinitrobenzene (TNB), a by-product of the incomplete oxidation of TNT. TNB is regulated as strictly as TNT. Additionally, over 70% of the reactor required treatment time for meeting target levels is due solely for TNB removal. This study evaluated the potential integration of zero-valent metallic species and advanced oxidation for the treatment of waters contaminated with TNT. The idea was to reduce treatment time, and thus, operational costs, when advanced oxidation is used as a stand-alone treatment technology by reducing TNT prior to oxidation. The use of zero-valent metals as the first treatment step transformed TNT into reduced organic compounds which were easily oxidized. The effectiveness of zinc, iron, nickel, copper, and tin as TNT reducing agents was evaluated. Zinc and iron were selected for further study based on their performance degrading TNT. Then, the reduction mechanism (pathway) and associated by-products of TNT reduction using zinc were examined using a zinc specimen manufactured by Sigma Corporation. Three amines were identified during reduction : 2-amino-4,6-dinitrotoluene, 4-amino-2,6-dinitrotoluene, and 2,4-diamino-toluene. Other intermediates were observed but not identified. Many of these reduction by-products adsorbed strongly onto the metal surface, significantly reducing the rate of TNT degradation during aging experiments. The aging of the metallic species was modeled using a power decay law parameter with the rate expression for TNT degradation. Corrosion promoters such as KCl addition, ozonation, and peroxone were evaluated as alternatives to reactivate zinc and iron to achieve steady TNT degradation. The addition of KCl performed significantly better than ozonation and peroxone. Furthermore, addition of KCl during the reduction step using iron or zinc generated organics that were successfully mineralized by ozonation or peroxone.
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The identification and analysis of acid mine drainage sources to the surface waters of the Robinson Run Sub-watershedBrothers, Christopher A. January 2001 (has links)
No description available.
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Water and Identity: An analysis of the Cauvery River water disputeAnand, Prathivadi B. 10 July 2004 (has links)
Yes / This paper focuses on the dispute over river Cauvery in Southern India. Among the causes of river water disputes are contested property rights, difficulty in enforcing such rights, conflict of uses and a lack of willingness to compromise. A co-operative outcome in such cases depends on several factors: asymmetry of power in a triadic relationship between a federal government and two riparian states (one upstream and one downstream). Other factors influencing co-operation are the extent to which the claims of river waters can be elevated from those of immediate riparian peoples to those of an entire state; the dominance of a masculine paradigm towards 'taming' river waters using 'hard' investments rather than 'soft' and decentralised alternatives. On the basis of district level data, the importance of river Cauvery to the hydrology, economy and polity of the two contesting states is examined. This analysis helps us to appreciate why the two riparian state governments have limited room to manouvre. Drawing from two brief case studies of Murray Darling Basin and recent litigation in the USA, and other international experiences of river water treaties, the paper identifies various implications for the resolution of Cauvery and other river water disputes.
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Evaluation, Development and Improvement of Genotypic, Phenotypic and Chemical Microbial Source Tracking Methods and Application to Fecal Pollution at Virginia's Public BeachesDickerson, Jerold W. Jr. 26 September 2008 (has links)
The microbial source tracking (MST) methods of antibiotic resistance analysis (ARA) and fluorometry (to detect optical brighteners in detergents) were used in the summers of 2004 and 2005 to determine the origins of fecal pollution at beaches with a past history of, or the potential for, high enterococci counts and posted advisories. At Hilton and Anderson beaches, ARA and fluorometry in the summer of 2004 detected substantial human-origin pollution in locations producing consistently high counts of Enterococcus spp. Investigations by municipal officials led to the fluorometric detection and subsequent repair of sewage infrastructure problems at both beaches. The success of these mitigation efforts was confirmed during the summer of 2005 using ARA and fluorometry, with the results cross-validated by pulsed-field gel electrophoresis (PFGE). Results at other beaches indicated that birds and/or wildlife were largely responsible for elevated enterococci levels during 2004 and 2005. The application of fluorometry proved difficult in opens waters due to high levels of dilution, but showed potential for use in storm drains.
An additional study developed and tested a new library-based MST approach based on the pattern of DNA band lengths produced by the amplification of the 16S-23S rDNA intergenic spacer region, and subsequent digestion using the restriction endonuclease MboI. Initial results from small known-source libraries yielded high average rates of correct classification (ARCC). However, an increase in the library size was accompanied by a reduction in the ARCC of the library and the method was deemed unsuccessful, and unsuitable for field application.
A final study focused on the potential for classification bias with disproportionate source category sizes using discriminant analysis (DA), logistic regression (LR), and k-nearest neighbor (K-NN) statistical classification algorithms. Findings indicated that DA was the most robust algorithm for use with source category imbalance when measuring both correct and incorrect classification rates. Conversely k-NN was identified as the most sensitive algorithm to imbalances with the greatest levels of distortion obtained from the highest k values.
Conclusions of this project include: 1) application of a validation set, as well as a minimum detectable percentage to known-source libraries aids in accurately assessing the classification power of the library and reducing the false positive identification of contributing fecal sources; 2) the validation of MST results using multiple methods is recommended for field applications; 3) fluorometry displayed potential for detecting optical brighteners as indicators of sewage leaks in storm drains; 4) the digestion of the 16S-23S rDNA intergenic spacer region of Enterococcus spp. using MboI does not provided suitable discriminatory power for use as an MST method; and 5) DA was the least, and k-NN the most, sensitive algorithm to imbalances in the size of source categories in a known-source library. / Ph. D.
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[en] THE IMPORTANCE AND OCCURRENCE OF PHTHALATES IN POTABLE WATERS AND SAMPLES FROM THE GUANABARA BAY ECOSYSTEM / [pt] A IMPORTÂNCIA E OCORRÊNCIA DE FTALATOS EM ÁGUA POTÁVEL E NO ECOSSISTEMA DA BAÍA DE GUANABARAISABELLA RODRIGUES LOUREIRO 24 June 2003 (has links)
[pt] Ftalatos são os plastificantes mais utilizados
industrialmente, estando disseminados em todos os
ecossistemas do mundo. Como são compostos exclusivamente
sintéticos, sua presença é indicativa da industrialização
de uma região. Sua toxicidade é baixa, porém existem
indícios de possíveis efeitos como interferentes
endócrinos, especialmente no sistema reprodutor masculino.
No Brasil, existem poucos estudos sobre a ocorrência e
comportamento dos ftalatos no meio ambiente. Nesta tese foi
estudada sua ocorrência em amostras de águas potáveis de
diversos bairros das cidades do Rio de Janeiro e Niterói e
do ecossistema da Baía de Guanabara (águas, sedimentos e
mexilhões), a qual recebe inúmeros aportes industriais.
Todas as amostras foram coletadas, extraídas em
fase sólida e analisadas por cromatografia em fase gasosa,
utilizando detecção por captura de elétrons. As da Baía
foram amostradas nas estações seca e chuvosa, em diferentes
anos. As extrações de todas as amostras obtiveram excelente
repetibilidade e recuperações superiores a 76%. As águas
potáveis do Rio de Janeiro e Niterói apresentaram teores de
ftalatos em concentrações muito menores do que as
informadas para cidades da Europa e Estados Unidos. Tais
teores puderam ser correlacionados com as extensões das
redes dos sistemas de abastecimento de ambas as cidades.
Todas as amostras da Baía mostraram contaminações
qualiquantitativas muito inferiores, quando comparadas a
outros ambientes costeiros. O estudo do biomonitoramento
ativo evidenciou a eficiência e rapidez da depuração dos
ftalatos nos mexilhões mais contaminados do ecossistema da
Baía de Guanabara. / [en] Phthalates are the most used plasticizers in industrial
products, worldwide distributed in environments. Their
presence is often used to indicate a region
industrialization degree. Although their reported toxicity
is low, phthalates are indicated for possible endocrine
disrupting effects, specially in male reproductive
system. In Brazil, there are few studies about the
environmental occurrence and distribution of phthalates.
This thesis studied the occurrence of those compounds
in potable waters samples from residential areas of Rio de
Janeiro and Niterói cities, and in samples from the
ecosystem of Guanabara Bay (waters, sediments and mussels),
which receives several industrial inputs. All the samples
were collected, solid-phase extracted and the phthalate
contents analyzed by gas chromatography with electron
capture detection. The ones from the Bay were sampled
during the dry and rainy seasons, in different years. All
the extractions presented excellent repeatability and
recoveries above 76%. The potable water samples from both
cities presented phthalate values considerably lower than
those reported for European and American cities. The
results could be correlated with the water net distribution
lengths for both cities. All results from the Bay
ecosystem showed lower contamination when compared to other
coastal environments. The controlled transplant proved
quick and efficient phthalate depuration of contaminated
organisms from Guanabara Bay.
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Rapid quantitative and qualitative screening of naphthenic acids in contaminated waters using condensed phase membrane introduction mass spectrometryLetourneau, Dane Rene 20 May 2016 (has links)
Naphthenic acids (NA) are a highly complex mixture of aliphatic carboxylic acids that may contain multiple rings and unsaturated double bonds, and are a subset of the naphthenic acid fraction components (NAFC), which can contain heteroatoms, unsaturations, and aromatic structures. Mono-carboxylated NAs can be classically represented by CnH2n+zO2 where z is a negative integer representing the hydrogen deficiency. NAs and NAFCs are components of the acid extractable organics (AEO) frequently associated with increased toxicity and observed at elevated concentrations in oil sands process waters (OSPW). Numerous chromatographic and mass spectrometry techniques have recently emerged to probe the composition and concentrations of these components. This thesis reports the use of a capillary hollow fiber polydimethylsiloxane (PDMS) membrane mounted on a probe interface that can be immersed directly into an aqueous sample. A methanol acceptor phase passing through the lumen transports analyte to an electrospray ionization source and a triple quadrupole mass spectrometer. This technique, termed condensed phase membrane introduction mass spectrometry (CP-MIMS), allows for rapid screening of m/z profiles and on-line quantification of NAs in complex samples within minutes. This thesis reports parametric studies of several model carboxylic acids and a standard naphthenic acid mixture (Merichem) involving the effect of sample pH on membrane transport and acceptor phase pH on ionization enhancement. Several quantitative strategies are explored including the use of an internal standard in the acceptor phase to correct for ionization suppression and variations in instrument sensitivity, and the use of selected ion monitoring (SIM) experiments to increase analytical sensitivity and potentially target specific NA isomer classes for quantitation. Analytical performance measures such as the linear dynamic range (1-2300 ppb [NA]T as Merichem), sensitivity (~1 ppb [NA]T as Merichem detection limit), precision (~20 %RSD for replicates of a single OSPW) and accuracy are reported. Quantitative results for various OSPW samples in the ppb to ppm range are reported as equivalents of several surrogates, including 1-pyrenebutyric acid (PyBA), Merichem, and a large-volume extract of northern Alberta OSPWs. The variety of quantitation strategies allows results to be compared with several other published methods. CP-MIMS results for three mid-range northern Alberta OSPWs are compared to analysis by Environment Canada with an average -21% bias. Results for five archived OSPWs spanning a wider concentration are compared to data from AXYS Analytical, with an average -49% bias. Applications of CP-MIMS as an in-situ monitor of removal efficiencies of NAs on adsorbents and real-time mass profile changes are also presented, along with some interpretation of the resulting high-resolution kinetic data to obtain decay constants. Using the targeted SIM method, adsorption decay can be followed in real-time for various isomer classes within the Merichem mixture, and kinetic data extracted to obtain decay constants for each. CP-MIMS is also used to characterize adsorption behavior for two activated biochars, including % removals for various loadings of each when added to stirred Merichem solutions. Preliminary multi-loading experiments are conducted with one biochar, and the ability of CP-MIMS to characterize adsorbent behavior by constructing adsorption isotherm plots is demonstrated. / Graduate
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Investigation of marine components of large direct seawater intake & brine discharge systems for desalination plants, towards development of a general design approachLe Roux, Maria 03 1900 (has links)
Thesis (MScEng (Civil Engineering))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: This investigation focused on the marine components of large direct seawater intake and brine
discharge systems for seawater desalination plants, with the main aim to provide an overall design
approach for these components.
Due to its complexity, an overall and systematic design approach, addressing all the components
(feedwater requirements, plant technology, marine structures and environmental issues) is required to
ensure an optimum design. A literature review was done on the various desalination technologies,
the main components of a seawater desalination plant, as well as the physical, hydraulic, operational
and environmental issues regarding seawater extraction facilities, marine pipelines and discharge
structures (diffuser).
In order to obtain practical input to the development of an overall design approach, information
regarding the marine structures of ten of the largest existing seawater desalination plants throughout
the world were obtained and compared with each other and the available technologies.
By way of example, the recently designed marine components of a new seawater reverse osmosis
desalination plant in Namibia were reviewed and, as part of this thesis, alternative conceptual
concepts which will include two additional components (sump and brine reservoir) were designed.
The alternative design was compared with the actual design in order to determine the feasibility of the
alternative in terms of operation and cost and subsequently provide input to the overall design
recommendations.
Furthermore, from the literature review it seems that there are still significant uncertainties regarding
the required performance of a brine (dense) outfall and this required more attention in terms of
environmental and hydraulic performance. Based on the Namibian plant, the diffuser configuration
was analysed in terms of its hydraulic and environmental performance and subsequently some
general guidance with specific respect to a brine diffuser was developed, which in turn formed part of
the overall design approach for the marine components.
Finally, the design approach for seawater intake structures, brine outfalls and the connecting marine
pipelines is provided in the form of flow diagrams. / AFRIKAANSE OPSOMMING: Hierdie ondersoek handel oor die mariene komponente van groot en direkte toevoer van seewater en
die sout-uitvloeisisteme van ontsoutingsaanlegte van seewater. Die doel is om ‘n oorsigtelike
ontwerpbenadering vir hierdie component te verskaf.
As gevolg van die kompleksiteit, is ‘n oorsigtelike en sistimatiese benadering, wat al die komponente
(vereistes vir toevoerwater, tehnologie by die aanleg, mariene omstandighede en omgewingsfaktore)
in ag neem noodsaaklik om die beste ontwerp te verseker.
‘n Literêre oorsig is gedoen ten opsigte van die tegnologie van verskeie ontsoutingsmetodes, die
hoofkomponente van ‘n seewater-ontsoutingsaanleg, asook die fisiese, hidrouliese, operasionele en
omgewingskwessies rakende die fasiliteite om die seewater te onttrek, die mariene pyplyne en die
strukture vir die afvloei.
Ten einde die optimum ontwerp te ontwikkel, is inligting oor die tegnologie en strukture van tien van
die grootste bestaande onsoutingsaanlegte in die wêreld bekom, bestudeer en vergelyk Hulle is met
mekaar vergelyk, asook met beskikbare tegnologie.
As ‘n voorbeeld is die nuut ontwerpte mariene komponente van die nuwe ontsoutingsaanleg in
Namibië, waar ontsouting d.m.v. omgekeerde osmose gedoen word ondersoek en as deel van hierdie
tesis, is ‘n alternatiewe konsep, wat twee bykomende komponente – ‘n opvangput en reservoir vir die
afloop – ontwerp. Hierdie alternatiewe ontwerp is met die werklike aanleg vergelyk om die
uitvoerbaarheid van die onderneming en die koste daaraan verbonde te toets. Dit is gebruik as
aanbeveling vir die oorhoofse ontwerp.
Uit die literêre oorsig blyk dit dar daar nog groot onsekerheid is oor die vereistes van die (digte)
waterafloop en dat meer aandag aan die omgewings- en hidrouliese aspekte gegee moet word. Met
die Namibiese aanleg as voorbeeld, is die struktuur van die spreiers t.o.v. hidrouliese werkverrigting
en die omgewing ontleed. Voortspruitend daaruit is algemene riglyne vir ‘n spesifieke spreier vir
afloopwater ontwikkel, wat op sy beurt weer deel vorm van die oorhoofse ontwerp vir mariene
komponente.
Laastens is die ontwerp vir die strukture vir seewater-invloei, die afloopwater en die mariene
verbindingspyplyne as vloeidigramme aangetoon.
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Modélisation du transport des nappes d'hydrocarbures en zone continentale et estuarienne / Numerical modelling of oil spill drifts in continental and estuarine watersGoeury, Cédric 22 October 2012 (has links)
L'application de la Directive Cadre sur l'Eau et l'obligation de surveillance de la qualité d'eau pour la consommation humaine et les activités récréatives ou industrielles, telles que la production d'eau potable, entraînent une forte demande pour des systèmes d'évaluation et de suivi de la qualité de l'eau. Le projet de recherche MIGR'HYCAR (http://www.migrhycar.com) a donc été mis en place pour répondre à un besoin opérationnel et à un défaut d'outils d'aide à la décision adaptés face aux déversements d'hydrocarbures en eaux continentales (rivières, lacs et estuaires) qui représente plus de 50% des déversements accidentels en France. Au cours du projet de recherche MIGR'HYCAR, un modèle mathématique de dérive de nappe d'hydrocarbures, composé d'un modèle lagrangien couplé à un modèle eulérien, a été développé dans la plate-forme hydro-informatique TELEMAC (http://www.opentelemac.org). Le modèle lagrangien décrit le mouvement de la nappe en surface en considérant celle-ci comme un ensemble de particules. Ainsi le modèle développé est capable de modéliser les principaux phénomènes agissant sur une nappe d'hydrocarbures une fois celle-ci déversée : convection, diffusion, échouage, re-largage, étalement, évaporation, dissolution et volatilisation. Bien que le phénomène de dissolution ne concerne qu'un très faible volume d'hydrocarbures, ce processus peut avoir des conséquences importantes du point de vue de la toxicité. Afin de suivre l'évolution du pétrole dissous, un modèle eulérien de suivi de traceurs a été adopté. La quantité de traceur dépend directement de la masse dissoute des particules lagrangiennes. Cette approche permet le suivi des hydrocarbures dissous dans la colonne d'eau. Des cinétiques effectuées en laboratoire ont pour but la calibration du modèle numérique. En complément de cas tests issus de la littérature et de cas réels, des résultats expérimentaux issus d'expérimentations effectuées en canal d'essai doivent permettre de vérifier et valider la qualité des simulations numériques sur des situations où les conditions ne sont que partiellement contrôlées / The application of the European Water Framework Directive on water quality for human consumption and industrial activities creates a need for water quality assessment and monitoring systems. The MIGR'HYCAR research project (http://www.migrhycar.com) was initiated to provide decisional tools for risks connected to oil spills in continental waters (rivers, lakes and estuaries), which represent more than 50% of accidental spills in France. Within the framework of this project, a new numerical oil spill model has been developed, as part of the Telemac hydro-informatics system (see: (http://www.opentelemac.org), by combining Lagrangian and Eulerian methods. The Lagrangian model describes the transport of an oil spill near the free surface. The oil spill model enables to simulate the main processes driving oil plumes: advection, diffusion, oil beaching, oil re-floating, evaporation, dissolution, spreading and volatilization. Though generally considered as a minor process, dissolution is important from the point of view of toxicity. To model dissolved oil in water, an Eulerian advection-diffusion model is used. The fraction of dissolved oil is represented by a passive tracer. This approach is able to follow dissolved hydrocarbons in the water column. Laboratory experiments were conducted to characterise the numerous kinetics of the processes listed above. In addition, meso-scale dynamic experiments in artificial channels and test cases derived from the literature are used to validate the numerical model
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"All Necessary Force": The Coast Guard And The Sinking of the Rum Runner "I'm Alone"Ricci, Joseph Anthony 20 May 2011 (has links)
Passage of the Volstead Act in 1920 expanded the mission of the U.S. Coast Guard. Law enforcement directives required officers to use "all necessary force" should a liquor smuggling vessel refuse the order to stop. On March 22, 1929, the Coast Guard Cutter Dexter sank the Canadian-flagged rum runner I'm Alone in the Gulf of Mexico, triggering an international incident that centered on "hot pursuit" and treaty jurisdiction. International encounters occurred frequently during Prohibition. The I'm Alone incident was the first sinking of a foreign flagged vessel that cost the life of a foreign national. The I'm Alone affair reflected the barriers any federal law enforcement agency faced in making Prohibition effective. The rum runner captain became a celebrity in Canada, while the Coast Guard was vilified. The Coast Guard amended boarding procedures after the incident cautioning officers about the possibility of accidental deaths.
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[en] ELETROCOAGULATION APPLIED TO TREAT SOLUTIONS WITH HIGH CONCENTRATION OF OIL / [pt] ELETROCOAGULAÇÃO APLICADA A MEIOS AQUOSOS CONTENDO ÓLEOANTONIO GUTIERREZ MERMA 19 September 2008 (has links)
[pt] Efluentes oleosos são gerados de muitas fontes, tais como:
indústrias petroquímicas, refinarias, plataformas de
petróleo, fabricação de maquinarias, e até mesmo, no
transporte, distribuição e armazenagem de óleo. O óleo
presente na forma de emulsão é difícil de separar. Para
quebrar essas emulsões, geralmente, são usados tratamentos
químicos, biológicos, eletroquímicos, ultrafiltração. O
processo de eletrocoagulação-flotação se inicia com a
dissolução do anodo produzindo espécies aquosas
(monoméricas, poliméricas) e precipitadas, espécies que
funcionam como coagulantes e floculantes. As mesmas causam a
desestabilização das emulsões através de mecanismos como a
neutralização de carga superficial, ponte interparticular e
coagulação por varredura, formando flocos de gotículas de
óleo. A dissolução do metal no anodo é acompanhada da
geração do gás hidrogênio no catodo. As bolhas são aderidas
aos flocos, carregando-os até a superfície, onde são
separados do reator, porém, dependendo da densidade deles,
poderiam sedimentar-se. Neste trabalho, é avaliada a remoção
de óleo de uma emulsão sintético pelo processo de
eletrocoagulação-flotação. Avaliou-se a influência dos
principais parâmetros de operação na taxa de redução
da demanda química de oxigênio (DQO): concentração inicial
do óleo; densidade de corrente; separação entre eletrodos;
pH da solução; concentração de eletrólito. O efluente
sintético foi preparado a partir de óleo Shell Talpa 30 e
Oleáto de sódio como surfatante. Foi adicionado NaCl para
aumentar a condutividade da solução. O pH inicial da emulsão
foi de 8,70. O potencial zeta nessas condições teve um valor
médio de -75mV, valor este que indicou a estabilidade da
emulsão. / [en] The separation of emulsions or colloidal particles from
wastewater is a major concern for the petroleum, metal
manufacturing, food, textile, paper and hydrometallurgy
industries. The emulsion present is very stable due to the
presence of surfactants, so conventional methods can not be
applied and it is necessary to combine one or two treatment
processes for highly effective purification. Several
techniques have been applied to treat these types of oily
wastewater, e.g.: chemical, biological and electrochemical
destabilization, ultrafiltration. Electrocoagulation is
initiated by the oxidation of sacrificial anodes. The metal
ions released combine to the hydroxyl ions produced at the
cathode to form the corresponding metal hydroxides and
others species, which cause the destabilization of the
contaminants or particulate suspensions and form
flocs. The bubbles hydrogen gas capturing and floating the
flocs formed and separating from the liquid surface by
scraping or settling depending on density of
the flocs. In this work, the electrocoagulation technique
was studied in order to treat concentrated oil-water
emulsions chemically stabilized. This study was
mainly focused on the effects of operating parameters such
as: initial pH, current density, reaction time, NaCl
concentration, electrode distance and inlet
concentration on the abatement rate of chemical oxygen
demand (COD). The synthetic emulsion was prepared from Shell
- Talpa 30 oil (3g.L-1) and sodium dodecyl sulfate (1.0
g.L-1), also was added NaCl (3g L-1) for increasing the
conductivity of the emulsion. Under those conditions we had
a pH value around 8.70 and a zeta potential around -70mV,
showing a good stability of the emulsion.
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